1. Field of the Invention
The present invention relates to a lens barrel and an image pickup apparatus.
2. Description of Related Art
In recent years, there are many products using a lens barrel of a collapsible type in which an image-capturing optical system is integrated inside a barrel in order to achieve smaller sizes in image pickup apparatuses such as digital still cameras and digital video cameras.
Such a lens barrel has a movable lens, which is movably disposed along its optical axis direction, at a position in front of an imaging device that picks up an image of an object formed by the image-capturing optical system, a guide mechanism that guides the movable lens in the optical axis direction, and a drive mechanism that moves the movable lens in the optical axis direction (for example, see Japanese Patent Application Publication No. 2002-296480).
The lens barrel is put into a collapsible barrel mode by positioning the movable lens to a limit position in a back side toward the imaging device. Positioning of the movable lens to the limit position is performed by attaching a detection piece to the movable lens, providing a sensor such as a photo interrupter detecting the detection piece attached to a part of the barrel so that the sensor detects the detection piece when the movable lens is positioned at the limit position, and controlling the drive mechanism based on a detection signal from the sensor.